A conventional technology disclosed in JP 2008-250906 A is a technology in which a mobile robot moving autonomously estimates a vehicle position according to amount of movement and, by matching a passage detected by laser scan with map information acquired in advance, performs correction of the estimated vehicle position. The detected passage and the map information are treated as two-dimensional data when viewed in plan, and, when performing matching between them, only data in a predetermined range from a present location are used.
When error occurs in information of a detected passage because of an occurrence of error in the amount of movement, a difference occurs between a detected shape of the passage and the actual shape of the passage and the degree of matching between information of the detected passage and map information decreases, which prevents a vehicle position from being estimated with high accuracy.